As of 2010, the beadLOCK Pro costs about $120, while the Basic Starter kit is about $30. Each kit comes equipped to make 3/8" mortises, and additional drill guides are available for 1/4" and 1/2" mortises. They’re under $20 each for the Basic Kit and $40 each for the Pro.
The Basic Kit uses shims to control the position of the holes relative to the face. On the Pro, this is done by sliding and locking the drill guide assembly into position. Adding all the shims to the Basic will make the center of your mortise about 1-1⁄16" from the face, on center. The Pro allows you to get to the center of a 4 x 4 (nominal). Index lines on the jig must be aligned with layout lines on your work to properly position the guides.
Along with drill guides, the Pro provides mortise paring guides. Drill the holes, swap the hole guide for a paring guide, and use it to guide a chisel to change from overlapping holes to a conventional mortise.
I like the large tenon material (deep penetration and lots of glue surface) this system uses. You can also choose not to drill the overlapping holes and simply use the beadLOCK tools as doweling jigs.
Aligning the jigs across the thickness of the material is easy, but you’ll need to lay out and position the jigs on all your layout lines.